@yangguo: please look at the debugger part of the CL.
@ishell: please look at the rest.

Additionally:
- Ensure the LookupIterator for named properties does not accidentally get indexes in.
- Fix the return value for typed array assignments to be the incoming value.

BUG=v8:4137
LOG=n

Review URL: https://codereview.chromium.org/1178503004

Cr-Commit-Position: refs/heads/master@{#28954}